Silane-crosslinkable polymers, and compositions comprising these polymers, are well known in the art, e.g., U.S. Pat. No. 6,005,055, WO 02/12354 and WO 02/12355. The polymer is typically a polyolefin, e.g., polyethylene, into which one or more unsaturated silane compounds, e.g., vinyl trimethoxysilane, vinyl triethoxysilane, vinyl dimethoxyethoxysilane, etc., have been incorporated. The polymer is crosslinked upon exposure to moisture typically in the presence of a catalyst. These polymers have found a myriad of uses, particularly as insulation coatings in the wire and cable industry.
Important in the use of silane-crosslinkable polymers is their rate of cure. Generally, the faster the cure rate, the more efficient is their use. Polymer cure or crosslinking rate is a function of many variables not the least of which is the catalyst. Many catalysts are known for use in crosslinking polyolefins which bear unsaturated silane functionality, and among these are metal salts of carboxylic acids, organic bases, and inorganic and organic acids. Exemplary of the metal carboxylates is di-n-butyldilauryl tin (DBTDL), of the organic bases is pyridine, of the inorganic acids is sulfuric acid, and of the organic acids are the toluene and naphthalene didistannoxanes. While all of these catalysts are effective to one degree or another, new catalysts are of continuing interest to the industry, particularly to the extent that they are faster, or less water soluble, or cause less discoloration to the crosslinked polymer, or offer an improvement in any one of a number of different ways over the catalysts currently available for this purpose.